And if you are not a bird, then beware of coming to rest above an abyss.

We must understand how to hide in darkness in order to escape the gnat-swarms of utterly annoying admirers.

The greatest events-they are not our loudest but our stillest hours.

The dyed-in-the-wool teacher takes everything seriously only with respect to his students--himself included.

The finest and healthiest thing about science is, as in the mountains, the brisk air blowing around in it.--The spiritually delicate (such as artists) shun and slander science owing to this air.

On the heights it is warmer than those in the valley imagine.

A subject for a great poet would be God's boredom after the seventh day of creation.